A memory card, an information-recording medium, is commonly employed in mobile electronic devices, such as mobile phones, due to its space-saving design.
More features and higher portability are ever-greater demand for mobile electronic devices, leading to a need for smaller and higher-capacity memory cards. A further smaller and thinner memory card has been standardized, and this has prompted study of how to achieve higher capacity within the standardized dimensions of the memory card.
In response to these demands, a technology for making memory cards thinner has been disclosed (for example, refer to Patent Literature 1). More specifically, a memory chip is laminated in a positionally-displaced manner on another memory chip on a lead frame. Electrodes of the two memory chips and the electrode of a control chip placed on the lead frame are then connected to the lead frame, using a gold wire, to achieve a thinner memory card.
However, in the memory card disclosed in Patent Literature 1, electrodes are needed on the lead frame for wire-bonding all the memory chips and the control chip. This requires space for the electrodes and space for carrying the wire that links the electrodes or connects to the external electrodes. This impedes the downsizing of the memory card or mounting of a high-capacity memory chip that has a larger area.
In addition, to sterically-cross wires, narrow-pitch or long wiring is needed at some connecting points. Therefore, to seal narrow-pitch wiring with filling resin, low-viscosity thermosetting resin needs to be used, which has the disadvantages of a long curing time, a limited selection of processes or materials, and a limited reduction of manufacturing costs.
Furthermore, the quality of each mounted chip can be inspected only after all the chips have been mounted and sealed. Therefore, if a mounting failure has occurred in the first mounted chip, this mounting failure is not detectable until all the chips are in place and sealed. This results in lower yields and thus higher manufacturing costs.    Patent Literature 1: Japanese Patent Unexamined Publication No. 2004-13788